// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Collections.Generic;
 
namespace Microsoft.Extensions.AI.Evaluation.Console.Utilities;
 
internal static class ExceptionUtilities
{
    internal static bool IsCancellation(this Exception exception) =>
        exception switch
        {
            OperationCanceledException => true,
            AggregateException aggregateException => aggregateException.ContainsOnlyCancellations(),
            _ => false
        };
 
    private static bool ContainsOnlyCancellations(this AggregateException exception)
    {
        var toCheck = new Stack<Exception>();
        toCheck.Push(exception);
 
        var seen = new HashSet<Exception>();
        bool containsAtLeastOneCancellation = false;
 
        while (toCheck.TryPop(out Exception? current))
        {
            // To avoid infinite loops, ignore exceptions that were already seen.
            if (seen.Add(current))
            {
                if (current is AggregateException aggregateException)
                {
                    foreach (var innerException in aggregateException.InnerExceptions)
                    {
                        toCheck.Push(innerException);
                    }
                }
                else if (current is OperationCanceledException)
                {
                    containsAtLeastOneCancellation = true;
                }
                else
                {
                    return false;
                }
            }
        }
 
        return containsAtLeastOneCancellation;
    }
}